Progress in the development of the 170 GHz coaxial cavity gyrotron

The fabrication phase of an industrial prototype of a 2 MW, CW 170 GHz coaxial cavity gyrotron started recently. To verify experimentally the design of critical components, the previously used 165 GHz short pulse coaxial tube has been redesigned for operation at 170 GHz. After starting the gyrotron operation strong parasitic low frequency (LF) oscillations mainly at 260 and 330 MHz have been excited. Recently the LF oscillations have been suppressed and microwave measurements started.